I consider Himalayan balsam (Impatiens glandulifera) one of the most stunning plants to be found in the British countryside. It is tall and stately and the flowers are exquisite in the same way as orchids are. I fully appreciate why it was brought here as a garden plant. That said, now it’s here, it has definitely become that houseguest that doesn’t know when to leave. It is dominating the party and drunk all the wine. Glamorous and elegant at the start of the night, it is now causing a nuisance and needs to be removed.

The Himalayan balsam flower: stunning, stately but a nuisance in the British countryside. Photograph: John McKenna/Alamy

Some of its relatives however aren’t quite so forward. One in particular, the Mount Emei balsam (Impatiens omeiana), would definitely be more likely to be found in the corner of the room reading a book. This a rare flower indeed. It comes from a very small area on Mount Emei on the western rim of the Sichuan basin in China and is classed as Endangered by the IUCN Red List. Mount Emei is particularly rich botanically and has been designated a world heritage site. However the flora of the region remains threatened, particularly by the continued development of the tourism industry.

In Britain, Mount Emei balsam is a popular plant for those in the know. It’s a woodlander that enjoys moist shade, creating slowly spreading clumps of interestingly marked foliage. Its flowers are pale yellow and hang below the foliage, providing a lovely addition to an already exquisite plant. Its required conditions are such that it will probably never become a runaway commercial success, but if you have the right spot it is a wonder to grow. It is available in a number of different forms or “clones”, each of particular importance. You see, the Mt Emei balsam cannot produce seed unless it is pollinated by a genetically different individual of its own species; a different clone.

A problem often faced by cultivated plants is that once a garden-worthy form has been found, and can be propagated easily by cuttings or division, only that form is then grown at the expense of all the others. If the plant is not deemed worthy of further breeding work to make it more commercial, often the only clone that remains is the one that is shared via gardeners and small nurseries, so the genetic variability is lost. Sometimes this means that the hardiest, most attractive or even disease resistant clones remain unknown in cultivation, purely through a lack of effort to maintain a genetically diverse population.

This was destined to be the case with the Mount Emei Balsam. It was originally described in 1908 after its discovery by the famed plant hunter Ernest Henry Wilson, but it took until 1983 for it to be introduced from the wild to commercial cultivation by Don Jacobs at his nursery, Eco Gardens, in the USA. The particularly good form ‘Eco Hardy’ was selected and subsequently introduced and grown here in the UK. It looked like that was going to be that for I. omeiana; a form good enough for cultivation was found, and people didn’t need to look much further.

Impatiens omeiana ‘Ice Storm’ was introduced to cultivation from a Japanese nursery by Michael Wickenden. Photograph: Robbie Blackhall-Miles

Thankfully via the hands of plant breeders such as Michael Wickenden, Cedric Basset and Dan Hinkley, many other wild clones have now been introduced to cultivation and are proving popular enough that there is little chance they will be lost. Dan Hinkley’s collection, with its long narrow leaves, is particularly interesting. The exact locality on Mount Emei that it was collected from is known and, through the continuing use of its collection number (DJHC 98492), allows us to reinstate plants into the wild should we ever need to.

Of course all of this isn’t of that great an impact to gardeners; most would choose one of these clones on its aesthetic merits alone. But in conservation terms it is vital that these cultivars are preserved, as each one makes up a small piece in the genetic variety found within a species. Should the day come when the species is lost to the wild, we will have a small population instead of a single individual clone in cultivation.

So Impatiens omieana is having a party all of its own, except it’s a rather quiet affair. It’s happening in a shady, moisture retentive, corner and it’s not getting out of hand. It’s the kind of party that its bolder, brash, relative, Impatiens glandulifera, isn’t invited to. It is celebrating its own safety created through its own amazing diversity.